Bone conduction receiver mounting for combined hearing aid and spectacles



Oct. 2 8, 1958 c; LEWIS BONE CONDUCTION RECEEIVER MOUNTING FOR COMBINED HEARING AID AND SPECTACLES Filed Sept. 24, 1956' mvsuroag v GEORGE LEWIS av M, W [M Ade/r.

United States Patent BONE CONDUCTION RECEIVER MOUNTING FOR COMBINED HEARING AID AND SPECTACLES George Lewis, Paris, France, assignor to Compagnie Frangaise dAudiologie, Paris, France, a company of France The present invention relates to improvements in hearing aid apparatus of the type in which a hearing aid device is combined with spectacles.

More specifically, it relates to improvements in the method of mounting used for securing a bone conduction receiver to the frame of the spectacles, in the case when such a receiver is employed in the hearing aid part of the apparatus.

It'will first be recalled that a hearing aid is a device provided for facilitating perception of sounds to hard-of-hearing persons, and that it essentially consists of a microphone followed by an amplifier and a telephone receiver, or a bone conduction receiver, together with auxiliary elements for the electric power supply thereof and for adjustment or regulation of the power of amplified sounds. A bone conduction receiver is an electromechanical device transforming electric currents into mechanical vibrations and transmitting the latter to the bones of the skull of the wearer of the apparatus, in the'vicinity of his ear. Thisprocess of transmitting sounds to the inner ear of a deaf person is known to give good results in many instances where the inner ear is in reasonably good condition, although the middle ear may be seriously defective.

It is also known that hearing aids of either type air conduction or bone conductionmay be built in the shape of spectacles, with the various parts of the equipment housed inside the frame of said spectacles, the side bows of said frame then being usually broader and thicker than those of ordinary spectacles, due to the necessity of allowing suflicient space for accommodating thevarious parts of the amplifying equipment. In this case, to keep the bulk of the device at a minimum, a transistor amplifier is generally used, mainly because of its reduced battery power supply requirements and consequent size reduction. The microphone is secured to one side bow of the spectacle frame, for instance the left one, while the bone conduction receiver is secured to the other side bow, to avoid interaction elfects between them, possibly resulting in the sustained oscillation phenomenon known as acoustic feedback.

It has long been known desirable to mount the micro phone on the frame elastically or floating, as this obviously avoids subjecting it to mechanical vibrations other than sounds. However, experience has shown that the parasitic coupling which may exist between a microphone and a bone conduction receiver respectively secured to one and to the other of the side bows of a spectacle frame is not completely eliminated by such a simple arrangement, and that a certain amount of mechanical coupling still persists through the front piece of the spectacles, eventually resulting in detrimental effects. The object of the present invention is a method of bone conduction receiver mounting, the purpose of which is suppressing, or at least significantly reducing the said parasitic coupling.

According to the present invention, there is provided a method of mounting a bone conduction receiver on one Patented Oct. 28, 1958 ice side 'bow of the frame of a combined spectacles and hearing aid, in which said bow is provided, on the inner side thereof, i. e. on that side which faces the wearers head, with an aperture through which said bone conduction receiver protrudes and comes into contact with the said wearers head, and in which said receiver is secured to said bow through the agency of a resilient material, for instance a rubber sheet to which it is firmly secured, said material being secured to the edges of said aperture and preferably stretched thereon, and said receiver being so centered with respect to said aperture as to avoid any direct mechanical contact between said frame and receiver.

Further particulars and advantages of the invention will be better understood from the following detailed description of an embodiment thereof, made with reference to the annexed drawings, in which:

Figure 1 is a partial perspective view of a combined hearing aid and spectacles.

Figure 2 shows, with more detail, a part of a side bow of a spectacle frame to which a bone conduction receiver is fitted, this part of said side bow being that which rests on the external ear of the wearer.

Figure 3 is a cross-section view of said side bow, illustrating the method of securing said receiver to said bow and assembling it with its support.

On Fig. 1 is shown, in perspective view, a pair of hearing aid spectacles, of which the said figure only shows one half, for the sake of simplicity. The front piece 3 of the spectacles, provided, if necessary, with glasses adapted to the wearers eyesight, is connected through the hinge connection 2 to the side bow 1. The latter, of a curved shape, is provided with an indentation 4, which rests on the external ear of the wearer, just in the same way as with ordinary spectacles. The side bow 1 is thick and hollow, to allow inside accommodation of amplifying elements, and usually consists of a hollow body 5, open on its inner face (which is that shown on Fig. 1), and having the shape of a groove, on the edges of which a closing plate 6 is secured, by glueing for in stance, said plate covering said inner face on the whole of its length and width. The side bow 1 and the plate 6, are made of a plastic material, for instance cellulose acetate, which may easily be given the proper shape and assembled by glueing.

On Fig. 1 may still be seen a small lid 7, which is easily removable and which covers a hole provided for the inspection and eventual replacement of a dry cell battery for the power supply of the apparatus housed inside 5. On the same Figure 1 may also be seen what will be called hereinafter a contact button 9, rigidly secured to the vibrating part of the bone conduction receiver, and also housed inside 5.

When the spectacles are worn in the normal way, this button engages the head of the wearer, and more precisely comes into contact with the latters skin behind his car, so that the vibrations of the receiver be transmitted to his mastoid temporal bone. The parts played by elements 8 and 14, also shown on Fig. 1, will be explained in connection with the description of Fig. 2.

Figure 2 shows, in a more detailed manner, the righthand part of Fig. 1. On Fig. 1 firstly appears the already mentioned lid 7. The bone conduction receiver is housed behind the button 9, which is rigidly assembled hollow rivets such as 14, or by any other known means. It may also be advantageous to glue the said rubber sheet to plate 6.

Figure 3 is a cross-section view of. the device of Fig: urel2, supposed to becut by a plane perpendicular to that of Fig. 2, and passing through line 33 of the latter. On Fig. 3 is shown the plate 6 closing the hollow body 5 of Fig. 1, which constitutes the side, bow of the spectacles. Inside the available free space is..the, bone conduction receiver 15. On a circular aperture provided in the closing plate 6 is stretched a rubber sheet 13, secured to said plate 6 by the flange 8 and rivets 14, which pass therethrough (said rubber sheet 13 being possibly further glued to 6, as already mentioned). The bone conduction receiver 15 comes into contact by its projecting parts, with the rubber sheet 13 and is rigidly secured to the plastic material button 9 by the central screw 12, which thus assembles '13, 15 and 9. As shown .on Fig. 3, the edge of button 9 is rounded on that of its faces which touches the head of the wearer, to avoid the obvious inconvenience of a sharp edge, while the edge of its other face is bevelled, to reduce the outer diameter of button 9 in the vicinity of the edges of the aperture provided in plate 6 and to prevent accidental contact of said button with said edges, or more simply, to avoid reducing the resilience of the rubber sheet by its being pinched between said button and aperture edges.

With the arrangements which have just been described by way of example, it is possible, owing to the inertia of the mass of the-bone conduction receiver 15 and to its resilient mounting, to transmit the mechanical vibrations developed therein by the amplified microphone currents without at the same time transmitting the said vibrations to the solid material of the side bows and further to the microphone.

What I claim is:

1. Combined spectacles and bone conduction hearing aid apparatus, comprising a spectacle frame having two hollow side bows, a microphone housed in one of said side bows, an amplifier, and a bone conduction receiver fed from amplified microphone currents, an aperture 011 the inner face of the other of said side bows, a rubber sheet covering and stretched on said aperture, a thin metal flange securin said rubber sheet to the edges of said aperture, and means for securing said receiver to said rubber sheet.

2. Apparatus as claimed in claim 1, wherein said rubber sheet is further secured to the edges of said aperture by glueing means.

3. Apparatus as claimed in claim 1, wherein said flange is secured to said other of said side bows by rivets.

4. Combined spectacles and bone conduction hearing aid apparatus, comprising a spectacle frame having two hollow side bows, a microphone housed in one of said side bows, an amplifier, and a bone conduction receiver fed from amplified microphone currents, an aperture on the inner face of the other of said side bows, a rubber sheet covering, said aperture, means for securing said rubber sheet to the edges of said aperture, and means for securing said receiver to said rubber sheet wherein said receiver is assembled with said rubber sheet by a metal screw rigidly secured to the vibrating part of said receiver.

5. Combined spectacles and bone conduction hearing aid apparatus, comprising a spectacle frame having two hollow side bows, a microphone housed in one of said side bows, an amplifier, and a bone conduction receiver fed from amplified microphone currents, an. aperture on the inner face of the other of said side bows, a rubber sheet covering said aperture, means for securing said rubber sheet to the edges of said aperture, and means for securing said receiver to said rubber sheet, wherein a disc-shaped plastic material button is secured to the vibrating part of said receiver.

6. Apparatus as claimed in claim 5, wherein said discshaped button is provided with a rounded edge on one of its faces.

7. Apparatus as claimed in claim 5, wherein said discshaped button is provided with a rounded edgeon one of its faces and with a bevelled edge on the other of its faces.

8. Apparatus as claimed in claim 5, wherein said discshaped button is provided with bevelled edges on both of its faces.

9. Apparatus as claimed in claim 5,- wherein said discshaped button is provided with rounded edges on both of its faces.

References Cited in the file of this patent UNITED STATES PATENTS 2,417,153 Dorr Mar. 11, 1947 2,718,563 Nicholidies Sept. 20, 1955 2,733,302 Geib et 'al. Jan. 31, 1956 2,794,075 Morgan H May 28, 1957 FOREIGN PATENTS v 723,981 Great Britain Feb. 16, 1955" 737,115 Great Britain Sept. 1 .1,v 1955 

